1. Field of the Invention
The present invention generally relates to an attachment process for flexible substrates and a patterned sealant used therein and, more particularly, to an attachment process for flexible substrates and a patterned sealant used in the attachment process wherein bubbles are easily evacuated and the opening of the patterned sealant is automatically sealed in the pressing process under the atmospheric pressure.
2. Description of the Prior Art
In the manufacturing process for the liquid-crystal displays (LCDs), the liquid crystal material is filled in the patterned sealant through an opening and then the opening is sealed.
Conventionally, there are two methods for filling. One is vacuum filling by capillary phenomenon and the other is one drop filling (ODF). In vacuum filling, a panel comprising two attached substrates is first disposed in a vacuum chamber to be pumped and the opening of the patterned sealant between the two attached substrates is exposed to a liquid crystal material so that the liquid crystal material is sucked into the patterned sealant after the vacuum is broken. The opening of the patterned sealant is sealed after the panel is filled with the liquid crystal material and cleaned. Please refer to U.S. Pat. No. 6,552,772 for vacuum ODF as shown in FIG. 1, wherein a patterned sealant 10 is formed between the substrates 11, 12 that are disposed between the sucking plates in a chamber 13. The liquid crystal material 14 is dropped on the bottom substrate 12 and the chamber 13 is pumped. The patterned sealant 10 is then solidified after the top substrate 11 is attached to the bottom substrate 12. These two methods require vacuum pumping, which results in long manufacturing time and high equipment cost. Moreover, vacuum filling results in a waste of the liquid crystal material, and cleaning and sealing are required.
Accordingly, these two methods are not suitable for liquid-crystal filling and sealing for flexible liquid-crystal displays. On the contrary, the manufacturing process for flexible liquid-crystal displays can be performed under the atmospheric pressure with lost cost. However, there are still problems due to bubble formation during filling and sealing.